Experiment Study On Deformation Measurement In Mid-Temperature Environment For SnSb8.5 Welding Wire Using Dscm

SnSb8.5 Pb-free wire of 0.76 mm diameter which is made of environment friendly material has large elongation during tension and the maximum value can reached 62 %. So, the traditional extensometer isn't suit to testing condition. Other more, traditional extensometer isn't suit in the temperature environment and medium/ high temperature strain gages are more expensive. Also, there are some difficulties arisen during sticking. Hence, we use the non-contact method Digital Speckle Correlation Method (DSCM) to test the strain of SnSb8.5 welding wire.In this thesis, A set of hardware system was established based on DSCM strain measurement. It can perform the functions as follows: speckle making of specimen, adjusting of image size and images collecting. Also, we developed a professional program based on MATLAB workbench that has powerful functions of image processing and numerical value computing. It was proved to be a reliable method by experiment that using two ways of tensile test. Besides, this thesis applies Lagrange 2D interpolation to establishing the correlation coefficients and had solved the precision problem of integral pixel orientation. Also, it presents the academic analysis for sub-pixel orientation.During the strain test for SnSb8.5 in medium temperature environment with DSCM, we made speckles specifically on SnSb8.5 sample first using black spray-paint. Then, SnSb8.5 was tested several times under different temperature such as 20℃, 62℃ and 100℃. Images were collected by the self-assembled system. The deformation information of these images was obtained using software after the...